Process of removing hydrogen sulfide from a gas mixture

Abstract

The present invention relates to a process for removing hydrogen sulfide from a hydrogen sulfide containing gas comprising contacting the gas in a contactor with an aqueous reactant solution including a coordination complex of Fe(III) with a chelating agent to produce a purified gas and spent aqueous reactant solution containing solid sulfur and having an increased content of coordination complex of Fe(II) with the chelating agent, and regenerating the spent aqueous reactant solution by contacting in a first contact vessel the spent aqueous reactant solution co-currently with air to produce partly regenerated aqueous reactant solution followed by contacting in a second contact vessel partly regenerated aqueous reactant solution counter-currently with air to produce regenerated aqueous reactant solution which is removed from the lower part of the second contact vessel.

What is claimed is: 
     
       1. A process for removing hydrogen sulfide from a hydrogen sulfide containing gas mixture which process comprises contacting the gas mixture in a contactor at a temperature below the melting point of sulfur with an aqueous reactant solution including a coordination complex of Fe(III) with a chelating agent to produce a purified gas stream having a reduced hydrogen sulfide content and a spent aqueous reactant solution containing solid sulfur and having an increased content of a coordination complex of Fe(II) with the chelating agent, and regenerating the spent aqueous reactant solution to obtain a regenerated aqueous reactant solution by contacting in a first contact vessel the spent aqueous reactant solution co-currently with a free oxygen containing gas to produce a partly regenerated aqueous reactant solution and contacting in a second contact vessel the partly regenerated aqueous reactant solution counter-currently with a free oxygen containing gas to produce regenerated aqueous reactant solution which is removed from the lower part of the second contact vessel. 
     
     
       2. The process of claim 1 which further comprises removing a sulfur-rich stream from the lower part of the second contact vessel below the location from which regenerated aqueous reactant solution is removed.